Method and device for the production of tubular structural components

ABSTRACT

The present invention provides a method for the production of a tubular structural component. A tubular moulding tool having an inner mould surface which is shaped corresponding to an outer surface of the structural component is provided. A support surface of an expandable support which is formed such that in an unexpanded state, it fills the moulding tool, leaving an expansion spacing of the support surface to the mould surface, is covered with a tubular fibre-woven fabric. After the support has been arranged in the moulding tool, the fibre-woven fabric is pressed against the mould surface by expanding the support and is infiltrated by a curable matrix. From another point of view, a device is provided for the production of a tubular structural component.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of PCT/EP2008/065355 and claims thebenefit of U.S. Provisional Application No. 61/007,492, filed Dec. 13,2007 and German Patent Application No. 10 2007 060 029.3, filed Dec. 13,2007, the entire disclosures of which are herein incorporated byreference.

FIELD OF THE INVENTION

The present invention relates to a method and a device for theproduction of a tubular structural component, in particular a fuselagebarrel section of an aircraft or spacecraft.

Although the present invention and the problem on which it is based canbe applied to any tubular structural components with any cross-sectionalshapes, they will be described in detail in respect of the production offuselage barrel sections of aircraft.

In the construction of aircraft fuselage, particularly for commercialaircraft, it is usual to prefabricate tubular or barrel-shaped fuselagesections individually and to assemble them into the finished fuselage ina subsequent final assembly. Materials which are used to an increasingextent are fibre composite materials, for example carbon fibrereinforced plastics materials (CFRP) which make it possible to achieve ahigh stability of the sections with a relatively low weight.

A fuselage barrel section based on fibre composite materials is producedaccording to a conventional method using a winding body as a positivemould, onto which layers of a fibre material pre-impregnated with aresin matrix (prepreg) are wound and subsequently cured, for example bya heat treatment. The fibre placement or winding procedure is verytime-intensive due to the size of the component and to different fibredirections of the prepreg layers.

Since it is possible for slight differences in diameter of adjacentfuselage barrel sections to impede the final assembly, the winding bodyhas to have a high dimensional accuracy and must not expand any furtherafter the fibre placement procedure, for example during a heattreatment. At the same time, it is necessary to configure the windingbody such that it can be split or collapsed, so that after the curingprocedure, it can be contracted inwards by splitting or collapsing andcan be removed from the fuselage barrel section. The provision of awinding body which combines these characteristics is associated withhigh costs.

In order to obtain a fuselage barrel section which has a smooth outersurface and correspondingly advantageous aerodynamic characteristics,pressure sheets are also applied for the curing procedure. In this case,there must not be any auxiliary material, for example tear-off orventilation fabric between the pressure sheet and prepeg-woven fabric asthis would result in a rough surface of the fuselage barrel section. Ingeneral, it is not possible to remove excess resin or air from the spacebetween the winding body and the pressure sheets. However, an inadequateremoval of resin or air results in porous and thus low-qualitycomponents.

Further problems are caused in that the thickness of the prepeg-wovenfabric is reduced during the curing procedure by the so-called settingpath, which is to be considered during shaping and when the pressuresheets are pressed on. However, the setting path of the prepreg materialcan vary as a function of the material charge and thus, for example whenthere is a charge with a relatively long setting path, this can giverise to porosity. Since the internal diameter of the fuselage barrelsection is predetermined in a fixed manner by the external diameter ofthe winding body, the external diameter of the fuselage barrel sectionis reduced during the gradual setting of the prepreg interlaid scrim.Consequently, the prepeg-woven fabric is pushed together in theperipheral direction of the section, which readily results in anundesirable waviness of the fibres.

SUMMARY OF THE INVENTION

It is therefore the object of the present invention to achieve a highquality at a low cost when tubular structural components and inparticular fuselage barrel sections are produced.

This object is achieved according to the invention by a method for theproduction of a tubular structural component which has the features ofclaim 1 and by a device for the production of a tubular structuralcomponent which has the features of claim 14.

The idea on which the present invention is based is to use for theproduction of the structural component a moulding tool which is alsotubular and is configured as a negative mould, i.e. it has an innermould surface which is a negative of the outer surface to be formed ofthe structural component. The term “tubular” as used herein is notrestricted to tubes with a circular cross section, but explicitlyincludes tubes with elliptical, rectangular or other randomly shapedcross sections, in which case the cross section does not need to beconstant over the length of the tubes, but can be narrowed, widened orshaped in another way.

In order to arrange fibre-woven fabrics on the inner surface of themoulding tool, a support is also provided which can be expanded, inother words can be selectively brought at least into an expanded and anunexpanded state. In the unexpanded state, the shape of the support issmaller than the space described by the inner surface of the mouldingtool such that the support can be arranged in this state inside themoulding tool. In so doing, there remains between the inner surface ofthe moulding tool and an outer surface of the support a minimum spacingwhich is termed here the expansion spacing.

The outer surface of the support which opposes the inner surface of themoulding tool when the support is arranged in the moulding tool servesas a support surface which supports the fibre-woven fabric to beprocessed during the production process. The fibre-woven fabric isprovided in tubular form and arranged on the support surface such thatthe support surface is covered by the tubular fibre-woven fabric. Forexample, the tubular fibre-woven fabric is pulled over the support whilethe support, in the unexpanded state, is freely accessible outside themoulding tool.

The support is then arranged in the moulding tool such that the supportsurface covered by the tubular fibre-woven fabric is opposite the innersurface of the moulding tool, the expansion spacing which is reduced bythe thickness of the fibre-woven fabric remaining between thefibre-woven fabric and the inner surface. The support is then expanded,as a result of which this remaining spacing is shrunk to zero and thefibre-woven fabric is pressed against the inner surface of the mouldingtool by the support surface of the expanded support. In a final step,the fibre-woven fabric held between the support surface and the innersurface of the moulding tool is infiltrated by a curable matrix.

The use of a negative mould which reproduces the outer contour of thefuselage barrel section makes it possible to observe the desiredexternal dimensions with a high degree of accuracy. The moulding toolcan be configured without a considerable constructive expense in onepiece or in a simple manner such that it can be opened outwards or canbe disassembled. The setup of the fibre-woven fabric on the support,regardless of the moulding tool and curing tool, makes it possible toprovide a plurality of supports suitable for a given moulding tool andto alternately charge one of the supports with fibre-woven fabricoutside the moulding tool, while another support is located in themoulding tool for curing. In this manner, it is possible to use themoulding tool and, if appropriate, a curing station in a continuousmanner, which reduces the production costs and shortens dead time.

The use of fibre-woven fabric which is infiltrated by a separatelyprovided matrix affords further advantages in terms of time and greaterfreedom in the construction of the structural components which have beenproduced compared to the conventional use of prepregs. Fibre undulationsare prevented due to the fact that the fibre-woven fabric is stretchedby the expansion of the support in the peripheral direction.

According to a preferred development, the expansion spacing is between 1and 10 cm, for example approximately 5 cm. With such a spacing,sufficient clearance remains between the support surface and the innersurface of the moulding tool in order to move the support into and outof the moulding tool in a particularly fast and contact-free manner,while on the other hand the tubular fibre-woven fabric is prevented frombeing overstretched during the expanding procedure.

According to a preferred development, the support surface is coveredsuch that fibres of a fibre layer of the fibre-woven fabric rundiagonally around the support. This advantageously allows the tubularfibre-woven fabric to expand radially, the angle of inclination of thefibres changing without the fibres being overstretched in theirlongitudinal direction. After the support has been covered, the tubularfibre-woven fabric is preferably longer than the structural component,such that when the support is expanded radially, the fibre-woven fabricis able to contract in its longitudinal direction, while stillcompletely covering the support surface.

According to a preferred development, the support comprises a pressuremembrane, the support being expanded by the production of a pressuredifferential between an inner region of the support and an intermediateregion between the pressure membrane and the moulding tool. The pressuremembrane exerts on the tubular fibre-woven fabric a uniform contactpressure which can be precisely adjusted by the pressure differential,over the entire inner surface of the tubular moulding tool, which allowsa particularly uniform shaping of the wall of the structural component.

To produce the pressure differential, the pressure in the inner regionof the support is preferably increased above atmospheric pressure.Suitable compression devices can be accommodated inside the support, sothat when the support is arranged in the moulding tool, the support canbe expanded without sealing off the intermediate region, for example.Alternatively or in addition, to produce the pressure differential, thepressure in the intermediate region between the pressure membrane andthe moulding tool is decreased below atmospheric pressure. This allowsthe inner region to be made accessible, for example for inspectionpurposes. The pressure membrane does not need to be configured for highabsolute pressures.

According to a preferred development, a step is furthermore provided forarranging a reinforcing element between the support surface and thefibre-woven fabric. This makes it possible to connect the reinforcingelement, for example a stringer, to be connected to the structuralcomponent in a single operation with the production of the structuralcomponent. The reinforcing element is preferably guided in at least oneguide slot which runs in a radial direction of the tubular mouldingtool, while the support is being expanded. The reinforcing element isthus guided precisely into the desired connecting position withouttilting.

According to a preferred development, the reinforcing element isarranged between the support surface and the fibre-woven fabric as apre-impregnated or non-impregnated semi-finished fibre product. Thereinforcing element is connected by jointly infiltrating the reinforcingelement and the wall of the tubular structural component and by a jointcuring process.

According to another preferred development, the reinforcing element isarranged between the support surface and the fibre-woven fabric as apre-cured semi-finished fibre product. This allows the co-bonding of thereinforcing element with the wall of the tubular structural component,in which case for example the curable matrix with which the tubularfibre-woven fabric is infiltrated, acts as an adhesive.

According to a preferred development, the reinforcing element isarranged in a correspondingly configured recess in the support surface.This facilitates the charging of the support with the reinforcingelement.

According to a preferred development, a placeholder is arranged in acavity between the reinforcing element and the tubular fibre-wovenfabric. During the curing procedure when the reinforcing element issubjected to the mutual pressure of the support surface and the innersurface of the moulding tool, this placeholder keeps the desired cavityof the reinforcing element free. The placeholder preferably has amembrane sheath, in which case a step is furthermore provided forexpanding the placeholder by increasing a pressure in the membranesheath. A placeholder which can be expanded in this manner can becontracted again after the curing procedure and can therefore be easilyremoved.

According to a preferred development of the device according to theinvention, at least one guide cover is provided for positioning on atleast one end of the moulding tool ad/or of the support. The guide coverhas a guide slot which runs in a radial direction of the tubularmoulding tool and is to guide the reinforcing element. During theexpansion of the support, the guiding slot guides the reinforcingelement precisely in a radial direction into the desired position on theinside of the structural component, irrespective of the shape of thereinforcing element and the shape of the support surface.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, the invention is described in detail on the basis ofembodiments with reference to the accompanying figures of the drawings.

FIG. 1A-C are schematic perspective views of a device for the productionof a fuselage barrel section of an aircraft according to a firstembodiment of the invention;

FIG. 2A-G are cross-sectional views of details of a device according toa second embodiment during the production of a tubular structuralcomponent; and

FIG. 3A-D are cross-sectional views of details of a device according toa third embodiment during the production of a tubular structuralcomponent.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

In the figures, the same reference numerals denote the same orfunctionally identical components, unless indicated otherwise.

FIG. 1A to 1C are three schematic perspective views of a device for theproduction of a fuselage barrel section of an aircraft, each of thethree figures showing different steps of a production method. Thefuselage barrel section to be produced is approximately in the shape ofa cylinder barrel, the cross section typically differing from the idealcircular shape and changing over the length of the section.

FIG. 1A shows a tubular moulding tool 102 with an inner surface 106which is shaped corresponding to the desired shape of the outer surfaceof the fuselage barrel section to be produced. The moulding tool 102 isa so-called negative mould, because its inner surface 106 forms anegative shape for the outer surface of the fuselage barrel section.Next to the moulding tool 102 is a support 110 for supporting a tubularfibre-woven fabric 114.

The support 110 is of an approximately cylindrical shape, havingapproximately the same length as the moulding tool 102 and an externaldiameter which is slightly smaller than the internal diameter of themoulding tool. Consequently, it can be arranged both inside and outsidethe moulding tool 102. The support 110 comprises an inner frame whichdefines the illustrated shape and its lateral surface 108 is covered bya resilient pressure membrane which separates an inner region of thesupport from the outside in a pressure-tight manner. For the simple,contact-free insertion of the support inside the moulding tool, thesupport and/or the moulding tool can be provided with rollers forexample (not shown).

The surface of the pressure membrane arranged around the lateral surface108 of the approximately cylindrical support 110 forms a support surface108 which supports the tubular fibre-woven fabric 114 during theproduction of the fuselage barrel section. At the start of theproduction method, the support 110 is arranged outside the moulding tool102. The tubular fibre-woven fabric 114 is cut to size and drawn overthe support 110 until it completely covers the support surface 108. Thefibre-woven fabric 114 used is, for example a non-woven fabric, forexample a so-called NCF (non-crimped fabric) which consists of carbonfibres or other suitable fibres and can be reinforced locally accordingto constructive details of the fuselage section to be produced. Thefibre-woven fabric 114 comprises a plurality of fibre layers ofdifferent orientations in which the fibres 116 run diagonally, as shownby way of example, i.e. spirally around the periphery of the support110. In further fibre layers (not shown), fibres run at otherinclination angles diagonally or parallel to the longitudinal directionof the support 110.

The length 118 of the cut tubular fibre-woven fabric 114 is greater thanthe length of the support 110 and of the moulding tool 102, such thatthe fibre-woven fabric 114 not only covers the support surface 108 ofthe support 110, but projects beyond the support 110 at both endsthereof.

FIG. 1B shows a subsequent step of the production method in which thesupport 110 covered by the fibre-woven fabric 114 has been moved intothe moulding tool 102. Since the diameter of the support 110 is smallerthan the internal diameter of the moulding tool 102, the support 110fits into the moulding tool 102 without the support surface 108contacting the inner surface 106 of the moulding tool. Instead, thesupport surface 108 and the inner surface 106 of the moulding tool 102run approximately parallel, a minimum spacing 112 of, for example 5-10cm remaining at any point between them. The fibre-woven fabric 114covering the support surface 108 projects at both ends out of themoulding tool 102 due to its length 118.

FIG. 1C shows a further step of the production method in which acompressor 205 has produced an excess pressure in the inner region ofthe support 110. The pressure membrane, forming the support surface, ofthe support is inflated by the excess pressure, such that the support110 is expanded radially beyond the dimensions of its inner frame. Theradial expansion of the support 110 stretches the tubular fibre-wovenfabric 114 in the direction of the periphery of the support 110. At thesame time, due to the fibres 116 which run diagonally around thesupport, the tubular fibre-woven fabric 114 has contracted in itslongitudinal direction up to a shortened length 119. In this respect,the tubular fibre-woven fabric 114 had initially been cut generouslysuch that it still completely covered the support surface even with itsshortened length.

In the illustrated expanded state of the support 110, the pressuremembrane presses the fibre-woven fabric 114 against the inner surface108 of the moulding tool due to the excess pressure in the inner regionof the support 110. In a further step, the fibre-woven fabric, fixed inthis manner, is infiltrated by a liquid, curable resin matrix 115, forexample in that the resin matrix is introduced from one end of themoulding tool 102, as indicated by arrows, into the gap between thepressure membrane and the moulding tool 102.

The resin matrix is then cured, for example by a heat treatment. Theexcess pressure is discharged from the inner region of the support 110,so that the support 110 returns into its original, unexpanded state andcan easily be removed from the moulding tool 102. The finished fuselagebarrel section is removed from the moulding tool 102. Sections which aremoulded such that they taper towards one end are removed from themoulding tool 102, for example in the direction of the other end.Alternatively, the moulding tool 102 can be configured in two or moreparts, such that it can be opened for the finished section to beremoved.

A further embodiment of the production method will now be described inmore detail with reference to FIG. 2A-G. FIG. 2A-G are eachcross-sectional views of a detail of the periphery of the support 110for different steps of the method.

FIG. 2A shows the mentioned detail of the support 110 in a startingstate in which a fibre-woven fabric has not yet been arranged on thesupport surface 108 and the support 110 is outside the moulding tool102. The support 110 comprises a rigid support frame 111 with asubstantially circular cross section. The support frame 111 is formedfrom aluminium, for example and has on its surface a large number ofsmall holes for charging with vacuum and/or excess pressure, which havenot been shown here to improve clarity. A slot-like recess 210 isconfigured in one location of its periphery to later receive areinforcing element. The periphery of the support frame 111 is flattenedin an edge region 211 on both sides of the recess 210.

The surface of the support frame 111 is covered by a pressure membrane200 which extends over the entire lateral surface of the overallapproximately cylindrical support frame 111 and is connected to thesurface of the support frame 111 in a pressure-tight manner at the edgesof the lateral surface. An inner region 202 between the pressuremembrane 200 and the support frame 111 is therefore sealed off in apressure-tight manner from the exterior. The pressure membrane 200 isconfigured as a plastics material film, for example.

FIG. 2B shows a state of the support 110 of FIG. 2A after a vacuum pump204 has been connected to the interior 202 and has evacuated it via thefine holes 213 in the surface of the support frame 111, of which onlyone hole 213 is shown here by way of example. The vacuum in the interior202 tightly suctioned the pressure membrane against the support frame111. In particular, the pressure membrane follows the contour of thesupport frame 111 as far as into the recess 120.

In FIG. 2C, a reinforcing element 208 with a T-shaped profile, as usedfor example in aircraft construction as a so-called T-stringer, has beeninserted into the recess 120. The horizontal bar 209 of the T-shapedprofile rests inside the flattened area 211 against the support frame111 covered by the pressure membrane 200.

In FIG. 2D, the pressure membrane 200 has been covered by a tubularfibre-woven fabric 114 consisting of carbon fibres. The outer surface108 of the pressure membrane 200 acts as the support surface 108,supporting the fibre-woven fabric 114, of the support 110. Thereinforcing element 208 is included between the support surface 108 andthe fibre-woven fabric 114 and is held in the recess 210. Since thehorizontal bar 209 of the T-shaped profile is also in a concealedposition inside the flattened area 111, the fibre-woven fabric 114 doesnot have a bulge above the reinforcing element 208, but follows a gentlecurve.

FIG. 2E shows the support 110 which has been prepared in this manner andhas been charged with the reinforcing element 208 and the fibre-wovenfabric 114, after it has been pushed into a tubular moulding tool 102.The support 110 is smaller than the interior of the moulding tool 102and is configured corresponding to the shape of said moulding tool tothe extent that a spacing 112 always remains between its support surface108 and the surface 106 of the moulding tool. In other words, thesupport surface 108 and the mould surface 106 run parallel to oneanother in the spacing 112 in the illustrated state. On the other hand,the fibre-woven fabric 114 and the pressure membrane 200 as well as thepressure membrane and the support frame 111 contact one another and areshown at a distance from one another in FIG. 2B-E merely for the sake ofclarity.

FIG. 2F shows the support 110 arranged in the moulding tool 102 afterthe interior 202 between the support frame 111 and the pressure membrane200 has been connected to a compressor 205 and has been subjected toexcess pressure through the fine holes 203. The excess pressure hasinflated the pressure membrane 200 such that it has expanded in a radialdirection 212 as far as the surface 106 of the moulding tool 102. Boththe pressure membrane and the fibre-woven fabric have been stretched bythe expansion. The reinforcing element 208 and the fibre-woven fabric114 have been guided by the expanding pressure membrane 200 to the mouldsurface 106 and, in the illustrated state, are pressed against the mouldsurface 106 with uniform contact pressure provided by the excesspressure. During the expansion procedure, the reinforcing element 208has been guided through the recess 120 in a radial direction 112 and, inthe illustrated state, is also still held in the recess 120, as in aguide slot, and is thus positioned precisely.

FIG. 2G shows the state after the space between the pressure membrane200 and the moulding tool 102 has been filled with a curable matrixsystem 115. The matrix 115 has infiltrated both the fibre-woven fabric114 and the fibre material of the reinforcing element 208, as indicatedby the hatching. The excess pressure in the inner region 202 of thesupport 110 is maintained during the subsequent curing procedure by aheat treatment. The excess pressure is then discharged and the finishedfuselage barrel section 100 is removed from the moulding tool 102.

FIG. 3A-D show another embodiment of the production method. The figuresare again each cross-sectional views of details of the periphery of thesupport 110 for different steps of the method.

FIG. 3A shows a state corresponding to FIG. 2B in which a pressuremembrane 200 has been arranged tightly along the surface of a supportframe 111, for example likewise by evacuating the interlying innerregion of the support. As in the above embodiment, a recess 120 for areinforcing element is configured in the support frame 111, said recesshaving here, however, the shape of a wide, trapezoidal trough.

In the state shown in FIG. 3B, a reinforcing element 208 which is formedfrom prepreg and has an Ω-shaped profile, a so-called Ω stringer hasbeen arranged in the recess 210. A cavity 304 to be configured in thefinished fuselage barrel section under the Ω-shaped profile of thestringer 208 is filled here by a placeholder 300 which is formed in thiscase by way of example from a membrane sheath 301 filled with compressedair. A tubular fibre-woven fabric 114 covers the support surface 108formed by the pressure membrane 200, the foot portion 306 of the Ωstringer and the outwardly facing side of the placeholder 300.

In the state shown in FIG. 3C, the support 110 prepared thus has beenarranged in a tubular moulding tool 102. An expansion spacing 112remains between the support surface 106 and the mould surface, as in theembodiment described above. In order to expand the support 110, itsinner region 202 is subjected to excess pressure and/or the intermediateregion 206 located between the pressure membrane 200 and the mouldingtool 102 is subjected to vacuum. In order to be able to guide the Ωstringer 208 precisely in a radial direction 212 during the expansionprocedure, a guide pin 502 is anchored in the placeholder 300 at bothends of the Ω stringer 208. Said guide pin slides in a radially 212running guide slot 302 which is recessed in a guide cover 500respectively fitted to the ends of the moulding tool 102.

FIG. 3D shows a state in which the pressure membrane presses the tubularfibre-woven fabric 114 together with the Ω stringer 208 and the includedplaceholder 300 against the inner surface 106 of the moulding tool 102by the applied pressure differential between inner region 202 andintermediate region 206. In subsequent steps, the fibre-woven fabric 114and the Ω stringer 208 are jointly infiltrated by a resin matrix andcured. In so doing, the introduced matrix and the resin materialcontained in the prepreg of the Ω stringer 208 are combined. After acuring heat treatment, the excess pressure in the inner region 202 andthe vacuum in the intermediate region 206 are discharged and the curedfuselage barrel section is removed from the moulding tool 102. After theexcess pressure in the interior of the placeholder 300 has also beenreleased, said placeholder is removed below the Ω stringer 208 in orderto free its cavity 304.

Although the present invention has been presently described usingpreferred embodiments, it is not restricted thereto, but can be modifiedin many different ways.

For example, reinforcing elements of various other profiles can be used.It is possible to produce fuselage barrel sections and other tubularstructural components with complex, tapering cross sections, door andwindow openings.

LIST OF REFERENCE NUMERALS

-   100 structural component-   102 moulding tool-   104 outer surface-   106 mould surface-   108 support surface-   110 support-   111 frame-   112 expansion spacing-   114 fibre-woven fabric-   115 matrix-   116 fibres-   118 length of the fibre-woven fabric before expansion-   119 length of the fibre-woven fabric after expansion-   200 pressure membrane-   202 inner region-   203 hole-   204 vacuum pump-   205 compressor-   206 intermediate region-   208 reinforcing element-   209 horizontal portion-   210 recess-   211 flattened area-   212 radial direction-   300 placeholder-   301 membrane sheath-   302 guide slot-   304 cavity-   306 foot portion-   500 guide cover-   502 guide pin

1. A method for producing a tubular structural component, comprising thesteps of: providing a tubular moulding tool which has an inner mouldsurface shaped corresponding to an outer surface of the structuralcomponent; covering with a tubular fibre-woven fabric a support surfaceof an expandable support which is formed such that in an unexpandedstate, it fills the moulding tool while leaving an expansion spacing ofthe support surface to the mould surface; arranging the support in themoulding tool; pressing the fibre-woven fabric against the mould surfaceby expanding the support with radial expansion of the fibre-wovenfabric; and infiltrating the fibre-woven fabric with a curable matrix.2. The method according to claim 1, wherein the support surface iscovered such that fibres of a fibre layer of the fibre-woven fabric rundiagonally around the support.
 3. The method according to claim 1,wherein after the support has been covered, the tubular fibre-wovenfabric has a greater length than the structural component.
 4. The methodaccording to claim 1, wherein the support comprises a pressure membrane,the support being expanded by the production of a pressure differentialbetween an inner region of the support and an intermediate regionbetween the pressure membrane and the moulding tool.
 5. The methodaccording to claim 4, wherein to produce the pressure differential, thepressure in the inner region of the support is increased aboveatmospheric pressure.
 6. The method according to claim 4, wherein toproduce the pressure differential, the pressure in the intermediateregion is reduced below atmospheric pressure.
 7. The method according toclaim 1, wherein furthermore a step of arranging a reinforcing elementbetween the support surface and the fibre-woven fabric is provided. 8.The method according to claim 7, wherein furthermore a step of guidingthe reinforcing element, during the expansion of the support, in aradial direction of the moulding tool is provided.
 9. The methodaccording to claim 7, wherein the reinforcing element is arrangedbetween the support surface and the fibre-woven fabric as apre-impregnated or non-impregnated semi-finished fibre product.
 10. Themethod according to claim 7, wherein the reinforcing element is arrangedbetween the support surface and the fibre-woven fabric as a pre-curedsemi-finished fibre product.
 11. The method according to claim 7,wherein the reinforcing element is arranged in a correspondinglyconfigured recess in the support surface.
 12. Method according to claim7, wherein furthermore a placeholder is arranged in a cavity between thereinforcing element and the tubular fibre-woven fabric.
 13. The methodaccording to claim 12, wherein the placeholder has a membrane sheath andfurthermore a step of expanding the placeholder by increasing a pressurein the membrane sheath is provided.
 14. A device for producing a tubularstructural component, comprising: a tubular moulding tool which has aninner mould surface shaped corresponding to an outer surface of thestructural component; an expandable support which is formed such that,in an unexpanded state, it fills the moulding tool while leaving anexpansion spacing between a support surface of the support and the mouldsurface, the expansion spacing amounting to 1 to 10 cm; a means forexpanding the support such that when the support surface is covered witha tubular fibre-woven fabric and when the support is arranged in themoulding tool, the support surface radially expands the fibre-wovenfabric and presses it against the mould surface; and a means forinfiltrating the fibre-woven fabric with a curable matrix.
 15. Thedevice according to claim 14, wherein the support comprises a pressuremembrane, the expansion means being configured to produce a pressuredifferential between an inner region of the support and an intermediateregion between the pressure membrane and the moulding tool.
 16. Thedevice according to claim 15, wherein the expansion means comprises acompressor for increasing a pressure in the inner region of the supportabove atmospheric pressure.
 17. The device according to claim 15,wherein the expansion means comprises a vacuum pump for reducing apressure in the intermediate region below atmospheric pressure.
 18. Thedevice according to claim 14, wherein the support comprises a recess forinserting a reinforcing element.
 19. The device according to claim 18,wherein furthermore a means for guiding the reinforcing element, duringthe expanding of the support, in a radial direction of the moulding toolis provided.
 20. The device according to claim 19, wherein the guidingmeans comprises at least one guide cover for fitting to at least one endof the moulding tool and/or of the support, the guide cover having aguide slot running in a radial direction of the tubular moulding toolfor guiding the reinforcing element.